(Topic ID: 242076)

Gottlieb System 3 Short

By JReedie

5 years ago



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    #1 5 years ago

    I've posted a few threads on this topic as every time I clear the problem it moves somewhere else.

    I have a customer with a Street Fighter 2, currently fuses F8 (BACKBOX GI) and F9 (PLAYFIELD GI) Are shorting together.

    Every bulb holder is shorted out which made me search for shorts further than just the playfield. I separated the fuse holders just to be certain there was nothing bridging them, with a continuity tester the right hand wire on fuse F8 coming from the transformer is shorting somewhere to the left hand wires of F9 going to the playfield. I disconnected all connectors and tried to trace the issue, if I disconnected A12J9 (transformer) the short dissappears. Also if I disconnected A9J3 (going to A Q T Relays) the short dissappears. I checked both connectors for any shorted wires/pins and found nothing, a also checked all relays for anything shorting the switches out and found nothing.

    Any help would be greatly appreciated as this has become a very frustrating issue that the owner of the machine has been tracing for over 2 years

    Thanks
    James

    #2 5 years ago

    Hmmmm. On CBW schematics (also a System 3) it shows both F8 and F9 are tied together, by design, at the transformer side of the fuse holder. With these two fuses removed you should see a direct short on that side of the fuse holder. Double check your schematics for Street Fighter 2 to make sure we are seeing the same thing. Then measure in ohms, between the two fuse holders with both fuses removed on the sides not attached to the transformer.

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    #3 5 years ago

    Thanks for your response, Yes the SF3 schematics are the same as above. The short that I'm getting is from the transformer side of F8/F9 (Which makes sense if they're tied) to the playfield side of F9. But I don't understand what could be bridging those 2 lines to create a short

    #4 5 years ago
    Quoted from JReedie:

    Thanks for your response, Yes the SF3 schematics are the same as above. The short that I'm getting is from the transformer side of F8/F9 (Which makes sense if they're tied) to the playfield side of F9. But I don't understand what could be bridging those 2 lines to create a short

    Keep in mind that this is a volts AC supply to both branches. Make sure you are not measuring back through the transfomer winding by disconnecting either wire at pin 10 or 11 of the transformer secondary.

    #5 5 years ago
    Quoted from wayout440:

    Keep in mind that this is a volts AC supply to both branches. Make sure you are not measuring back through the transfomer winding by disconnecting either wire at pin 10 or 11 of the transformer secondary.

    It's kinda difficult as I don't have immediate access to the machine as it's at the customers arcade. Where should I be testing and what reading should I be looking for? I can't seem to figure out how the power from the transformer is shorting across the fuse holder to the playfield GI

    #6 5 years ago

    What are the symptoms of the problem? Fuses blowing, no lights? If you are measuring GI lamp sockets across the tabs with any of the lamps in either the backbox or playfield installed you are going to see shorts because of the installed lamps and/or fuses. You have to remove the fuses as well as all of the GI lamps to be measuring across lamp sockets for continuity.

    #7 5 years ago
    Quoted from minnesota13:

    What are the symptoms of the problem? Fuses blowing, no lights? If you are measuring GI lamp sockets across the tabs with any of the lamps in either the backbox or playfield installed you are going to see shorts because of the installed lamps and/or fuses. You have to remove the fuses as well as all of the GI lamps to be measuring across lamp sockets for continuity.

    ...and as I said, also remove the transformer from the equation if needed. That's basically going to appear as a short because it is just a coil of wire. Minnesota13 makes a good point on the symptoms. What lead up to your statement that the backbox GI and playfield GI are shorting together?

    #8 5 years ago

    I've only just recently started work on the machine as the arcades full time technician didn't know anything about pinball machines. The machine had been intermittently blowing fuse F9 for the playfield GI. When I got there F9 just had a load of fuse wire wrapped round it. After testing all the holders I found 1 which had shorted out and replaced it, GI was working fine since. About a month later I get a call saying the GI had blown again. The T10A fuse at F9 started to blow more and more often to the point now that it blows as soon as you power on the machine

    #9 5 years ago
    Quoted from JReedie:

    After testing all the holders I found 1 which had shorted out and replaced it

    The holder was shorted out? A short - meaning continuity to another part of the circuit?...or was it "open"(such as burned out, not conducting)

    If fuse F9 was blowing, which results in only the playfield lamps to go off, where does your suspicion that F8 is also shorted come into play?....or do both the lightbox and the playfield go off when F9 blows? (which is not supposed to happen)

    #10 5 years ago

    Your description is confusing because shorting from the transformer directly to the playfield essentially eliminates the current that would ordinarily flow through F9 (which means it shouldn't blow even if there were an undesired short).

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